Chapter 4: SCSI Commands
4-54
July 2004
81-81276-01 Rev A01
Active Partition
Only partition 0 is supported. The tape drive rejects any other value for this field
with a CHECK CONDITION status and the ILLEGAL REQUEST Sense Key set.
Write Buffer Full Ratio
and Read Buffer Empty
Ratio
The tape drive sets these fields to 0 (unused). The tape drive uses an automatic,
adaptive mechanism to adjust its Full/Empty Buffer ratios dynamically according
to the average data rates over the SCSI bus.
Write Delay Time
This field indicates the maximum time that the tape drive waits with a partially full
buffer before forcing the data to medium (in 100 ms increments). The buffer Full/
Empty ratio, which is dynamic, can cause data to be written sooner than the Write
Delay time would indicate. The Write Delay Time defaults to 200 (C8h), causing
the buffer to be flushed in 20 seconds. The maximum value is 6500 (1964h), the
minimum value is 15 (0Fh), representing delays from almost 11 minutes down to
1.5 seconds.
Values between 0 and 15 are rounded down to 0. This causes the data to go straight
to the media without delay.
Byte 8
Code
Description
DBR
Must be 0 (Data Buffer Recovery not supported).
BIS
Must be 1 (Block Identifiers Supported in media
format).
RSmk
Must be 0 (Setmarks not supported).
AVC
Must be 0.
SOCF
Must be 0.
RBO
Must be 0.
REW
Must be 0 (Do not report Early Warning EOM on
reads).
Gap Size
This field is not used and is 0.
EOD Defined
End of Data Defined. This field must be 00h. The tape drive rejects any other
value.
EEG
Enable EOD Generation. This bit indicates that the tape drive generates an EOD.
The tape drive generates an EOD mark before any change of direction following a
write type operation. This bit must be 1.
SEW and Buffer Size
At Early Warning
Synchronize at Early Warning. This bit is 1. Buffer Size at EW is not supported
and must be 0.
Select Data
Compression
Algorithm
Setting this field to 1 enables hardware data compression. Setting it to 0 disables
hardware data compression.
Table 4-32.
Device Configuration Page — Field Descriptions
(Continued)
Field Name
Description
Summary of Contents for DLT1/VS80 SCSI
Page 1: ...DLT1 VS80 SCSI Interface Guide...
Page 6: ...DLT1 VS80 SCSI Interface Guide vi July 2004 81 81276 01 Rev A01 Notes...
Page 12: ...Table of Contents xii July 2004 81 81276 01 Rev A01 Notes...
Page 16: ...List of Figures xiv July 2004 81 81276 01 Rev A01 Notes...
Page 20: ...List of Tables xviii July 2004 81 81276 01 Rev A01 Notes...
Page 24: ...Chapter 1 Introduction 1 4 July 2004 81 81276 01 Rev A01 Notes...
Page 32: ...Chapter 2 General SCSI Bus Operation 2 8 July 2004 81 81276 01 Rev A01 Notes...
Page 42: ...Chapter 3 SCSI Messages 3 10 July 2004 81 81276 01 Rev A01 Notes...
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